The body of a 19th-century serial killer who will be portrayed by Leonardo DiCaprio in an upcoming film is being exhumed in suburban Philadelphia, in a move his relatives hope will quell rumours that he conned his way out of his execution and escaped from prison.
A Delaware County judge gave the go-ahead to exhume the remains of Dr HH Holmes in a court order dated March 9.
The Archdiocese of Philadelphia, which owns Holy Cross Cemetery in Yeadon, where the body was located, confirmed the exhumation was to take place but it was not immediately clear when the process started.
WCAU-TV in Philadelphia showed footage for a digger removing dirt from a grave at the cemetery on Friday.
Holmes, the pseudonym of New Hampshire-born doctor Herman Webster Mudgett, is believed to have killed an undetermined number people at his hotel of horrors during the 1893 Chicago World's Fair.
The hotel featured a bizarre labyrinth of windowless rooms, secret passageways, false floors, trapdoors, and a vault.
Most of the rooms had gas vents, which were controlled from Holmes' bedroom and many were soundproof and could be locked only from the outside.
But it was the murder of his business partner in Philadelphia that led to his conviction and hanging in 1896.
The exhumation and DNA analysis will be performed by the anthropology department at the University of Pennsylvania.
Mudgett's great-grandchildren, John and Richard Mudgett and Cynthia Mudgett Soriano, all of California submitted DNA samples to the university, according to their petition seeking the exhumation.
Judge Chad Kenney's order states that the remains are to be re-interred in the same grave after testing, whether or not they belong to Holmes.
John Mudgett's wife said the great-grandchildren, related to Holmes through his son with his first wife, Clara Lovering, were not commenting.
Holmes was executed in a public event at Philadelphia's Moyamensing Prison on May 7 1896.
Witnesses said he maintained his cool to the very end, even telling the executioner not to rush and the New York Times reported it took Holmes more than 15 minutes to die.
Holmes had left specific instructions for his burial - he was to be laid in a pine box and the box was then filled with cement, buried 10 feet in the ground and covered again with cement.
Nevertheless, rumours started swirling that he had managed to swap another convict to be executed in his place and went free.
Holmes was the subject of the 2003 best-selling book, The Devil In The White City, by Erik Larson, on which the film is based.
"I have absolute confidence the body in that grave is Holmes," Larson said on Wednesday.